1. Field of the Invention
The present invention relates to a molding method of a weather strip in which a molded portion is molded at an end of an extruded portion of the weather strip, and the extruded portion is formed by extrusion, and a mold for molding the molded portion.
2. Related Art
A seal between a door of an automobile and a peripheral part of a body opening is accomplished by a door weather strip attached to an outer part of a door frame provided at an outer peripheral portion of the door, and/or an opening weather strip attached at a flange of the peripheral part of the body opening. Incidentally, a seal between a door glass and the door is accomplished by a glass run attached to a channel at an inner part of the door frame.
As shown in FIG. 15, a door weather strip 110 is formed along a door frame (not shown), and includes extruded portions 117, linearly formed by extrusion, which are portions to be attached to an upper portion, front and rear side portions, and a lower portion of the door frame, and a molded portion 116 molded by molding which is a portion to be attached along the corner portions of the door frame.
The extruded portions 117 include an attachment base 111 (hereinafter referred to the base) to be attached to the door frame, and a hollow seal portion 112 integrally formed from the base 111, and to come in contact with the peripheral part of the body opening for sealing.
The shapes of the cross sections of the end faces of the molded portion 116 are formed in the same manner as the shapes of the cross sections of the extruded portions 117 to which the end faces are respectively connected.
Molding of the molded portion 116 is carried out by injecting a molding material into a cavity 120c formed between an upper mold 121 and a lower mold 122 of a molding device 120 as shown in FIGS. 16 to 18. When the molded portion 116 is molded, the extruded portions 117 and the molded portion 116 are integrally adhered by vulcanization and deposited simultaneously with the molding. For this reason, the ends of the extruded portions 117 are clamped by a holding portion 120b of the molding device (e.g., see, JP-B2-4-9645 and JP-B2-7-49203). At this step, the extruded portions 117 are required to be strongly clamped so as to be prevented from coming out of the molding device 120 by the pressure of the molding material injected into the cavity 120c. 
Clamping of the ends of the extruded portions 117 is accomplished by pressing outer surfaces of ends of the extruded portions 117 by an inner core 129 formed integrally with an insertion core portion 127 of the molding device 120, a first holding core 123, a second holding core 124, a third holding core 125, and a fourth holding core 126 as shown in FIGS. 16 to 19. FIG. 17 shows a cross section in a direction at right angles to the longitudinal direction of the extruded portion 117 at the rear side portion in the molding device 120.
FIG. 18 shows a cross section along the longitudinal direction of the extrusion portion 117 in the holding portion 120b of the molding device 120. The extruded portion 117 is clamped by the holding portion 120b of the molding device 120. Thus, into the cavity 120c, the molding material for the molded portion 116 is injected. In the inside of the hollow seal portion 112 of the extruded portion 117, the insertion core portion 127 is inserted, and it supports the extruded portion 117 from inside when the end thereof is pressed.
An enlarged cross section of the pressed portion is shown in FIG. 19. In the cavity 120c, an unvulcanized rubber material which is a molding material is injected. At this step, in order to prevent the end of the extruded portion 117 made of sponge rubber from coming out of the holding portion 120b, a convex portion 127b is formed at the outer periphery of the insertion core portion 127. With this configuration, the end of the extruded portion 117 is compressed.
When the molded portion 116 is molded, the molding device 120 has been heated for vulcanization because the molding material is rubber. The extruded portion 117 has been already vulcanized, and hence it will not be molten by the heat of the molding device 120. However, the clamped end of the extruded portion 117 is fixed in shape by heat while being compressed as shown in FIG. 20, so that a concave portion 117b is formed. In this case, not only the inner side of the extruded portion 117, but also the outer side is drawn to the inner side, so that a concave portion 117c is formed. This unfavorably causes a problem of degradation of appearance of the end of the extruded portion 117 of the door weather strip 110.
When the amount of the end of the extruded portion 117 to be compressed is reduced, the depths of the concave portions 117b and 117c are reduced. However, the clamping force on the end is reduced, so that the end becomes more likely to come out of the molding device 120 by the pressure of the molding material for the molded portion 116.